Firing head for gun perforators



Nov. 13, 1945.

J. G. SMYLIE FIRING HEAD FOR GUN PERFORATORS 2 Sheets- Sheet 1 FiledAug. 51, 1944 INVENTOR.

'J'AHES 6.5mm E BTTOR/VEY.

NOV. 13, 1945. J s l 2,388,938

FIRING HEAD FOR GUN PERFORATQRS Filed Aug. 31, 1944 2 Sheets-Sheet 2Patented Nov. 13, 1945 FIRING HEAD FOR GUN PERFORATORS James G. Smylie,Houston, Tex.

Application August 31, 1944, Serial No. 552,165

14 Claims.

The invention relates to a firing head for gun perforators of the typewhich are lowered into a well bore in order to perforate a well casing.

Considerable difiiculty is encountered with gun perforators due to thefact that they are lowered many thousands of feet into a well bore inthe column of liquid in the well and are subjected to the pressure ofthe static head of such column of liquid. This pressure often affectsthe firing mechanisms which have been used heretofore andv in someinstances has caused the premature firing of the gun, thus damaging thewell or the firing mechanism has failed to operate when the properlocation has been reached.

It is, therefore, one of the objects of the present invention to providea firing mechanism which is normally locked against operation until thedesired elevation ha been reached and the tool subjected to apredetermined number of revolutions by rotating the operating pipe owhich it is connected, all of which operations must be per formed beforeit is possible to fire the gun.

It is another object of the invention .to provide a safety firing headfor gun perforators.

Another object of the invention is to provide a firing head for gunperforators for operation upon rotation of the body relative to ananchor disposed in the well bore.

Still another object of the invention is to provide a combination firinghead and fiowpipe for gun perforators so that the flow of fluid enteringthe well after the perforations are made can pass upwardly through thefiring head to the surface.

A still further object of the invention is to provide a firing headfor'gun perforators which may remain in the well bore after theperforations are accomplished and serve as a flow pipe for the-fluidfrom the formation.

Still another object of the invention is to provide a firing head whichcan be utilized to fire a gun perforator and thereafter manipulated toanchor the firing head in the well as a flow head.

Other and further objects of the invention will be readily apparent whenthe following description is considered in connection with theaccompanying drawings wherein:

Fig. 1 is a vertical section of the tool in the position in which it islowered into the well with the firing mechanism locked againstoperation.

Fig. 2 is a-side elevation of the construction of Fig. 1.

Figs. 3 and 4 are sections taken on the lines 3-3 and 4-4 of Fig. 1respectively.

Fig. 5 is a vertical sectional view of the tool in the well after havingbeen operated to unlock the firing mechanism and showing the upp rportion of the firing head in such position.

Fig. 6 is a sectional View which is a continuation of Fig. 5 andillustrates the firing-mechanism about to be released. M H

Fig. '7 is a section taken on the line Fig. 5. Fig. 8 is a section takenon the line 8.l8- of Fig.6. 'f j The firing head or tool is made up ofabody 2 which has a nipple 3 threaded at 4 in its lower end. This nipplehas a'reces's 5 in which the plug 6 carries a plurality of primers ordetonators 8 disposed in position to fire into the con duits or passages9 whichextend down into the gun perforating mechanism not shown. Thereare preferably four ,of these detonators, all of which are fired toinsure the eXplosion'o-f the gun perforator. I p

The plug 6 is formed with atapered socket or IFW]. u in which thehammers l2 are-arrangedto' seat. These hammers form a circular memberhaving the tapered surfaces 13 thereon to (:0 operate with the bowl II.The lower ends ,of the hammers have a rid e l4 thereonto' strike thedetonators 8.

pref

These hammers are normally urged toward detonators by a spring [6arranged in the recess 5. The hammers, however, are restrained frommovement against the detonators by means of the plunger ll engaging thetapered surfaces l8 on the inner lower portion of the hammers .l 2. Thespring I6 urges all of the hammers downwardly, but they are limited inthis movement by abutk ment against the plunger I! which preferablybears against the plug 6 at the point 20 so-as to insure the locking ofthe hammers against further downward movement.

This plunger I! is carried by a rod 22 extends through a series ofpacking or stuffing boxes 23 toinsure that there will be no leakage intothe chamber 5 around the detonators 8. .This

rod 22 has a nut 24 adjustably arranged on its upper end and the rodpasses through the opening 26 in a plate 21 carried by the rods 23'which pass through the openings 29 in the upper ..p i-f tion of the body2. A cap 3!) serves to enclose the upper end of the rod 22 injury.

of slots 39 therein which receive the shoes 40 and protect it againstThe rods 28 are connected to a collar 35 which is mounted in theanti-friction bearings 35 in the body 31 of a cage 38. This cage has aplurality.

on the inside of the cage. These shoes normally bear against the insideof the casing 45 as best seen in the top of Fig. 5.

The inside of this body 31 has the recess 46 therein which carries asplit spring ratchet nut 51- having the ratchet threads 48 therein. Thetwo halves of this nut are held together by the springs 49 as best seenin Figs. 1 and 2.

A mandrel 50 is threaded at in the upper end of the body 2 of the firing,head, lbutiis iboth slidable and rotatable in the body 31 of the firinghead and the sleeve 42 thereof. This mandrel has ratchet threads 52thereon to latch the I ratchet threads 48 in the nut 4-! .so thatthe-entire cage 38 may move upwardlyrelative to the mandrel, or if thecage is held stationary rthe mandrel will move downwardly with .respectthereto. These threads face in one direction, however. so that rotationof the mandrel will cause axial movement in one direction, but a sharppull on the 'mandrel in the other direction will cause the threads onthemandrel to slide throughthe threads onthenut by expanding against'thetension of'the springs 49 so that .themandrel may be resetmreturnedto its orig inal position relative tot'he cage by such a sharp ,pull.

In actual operation-the 'partswill'be assembled as shown in Figs. 1 and2 and the tool will be lowered into the well bore through the casing 45to nearly "the "elevation where the perforating is to be accomplished.In fact it will be lowered so that thebtille'ts to 'be dischargedareprobztbly somewhat above "the intended perforation. During thislowering operation the "drag shoes '40 .w'ills'lide along the'inside,of'the casing and when the mandrel is rotated they will tend to holdthe cage 38 against rotation. its the rotation proceeds the mandrel 5Dandthe body 2 will move downwardly 'as the threads 52 on the mandrelmove through the threads 48 in the nut 41 to the position shown in Fig.5. This relative movement between the *body and'the cage causes anidentical relative longitudinal movement between the plate '21 and thebody 2 0f the firing head. This movement is sufiicient to cause theplate "to move against the nut to the position shown in Fig. 6 whereuponcontinued movement of the cage and the fir-ing 'head away from eachother causes the *rod 2-2 to move relative to the body 2. This *movementpicks up the hammers ['2 due to movement of the plungers l andcauses thehammers tofoe lifted against the :compression of the spring 4% so as tocook thespring and urge the hamme i2 downwardly.

"Il'le hammers are not released, however, until they have been raisedsuflieierftly to expand laterally and permit the plunger =1"! "to passupwardly through the taperedarea 1'8 which has become enlarged'as seenin Fig.6.

'Dnlya slight additional movement beyond shown in Fig. *6 will allow thehammers to slide downwardly around the plunger 11 due to the force of.thespring I15 so that'they'willbe snapped against the detonators 8 toeffect the firing thereof.

'It seems obvious from this arrangement that there can be no accidentalor premature firing of the detonators and the operator can obviously setthe tool so that he knows the number of rotaltions of the mandrel 5Bwhich will be required inorder to effect the firingo'f the detonators.In this 'manner the operator knows precisely when the 'firing .is totake place and he knows that the movement of the parts is such that thebuillets will perforate the casing at the intended elevation and thatthe tool is now in position to receive a flow of fluid from theperforations. Such flow will enter the window 60 in the body 2 and maymove into the passage 6! which extends upwardly through the mandrel intothe operating pipe which may be a tubing, drill stem or productionstring of pipe. In this manner a. sample of the fluid may be obtained atthe surface if desired.

Another feature or combination 'of the firing head is that the rods 64connected to the sleeve 42 of the cage may have connected thereto anyconventional type of slips or slips and packer so rthat the firing headmay be anchored in the well and form a seal inside of the casing tocompel the :fiow of zfiuid upwardly through the passage 6| inthemandrel.

The slips may be of a suitable type which can he set by raising up onthe mandrel 50 and then setting down the weight of the pipe thereon .andthe packer may be similarly set as .is well understood'in the art. Theanchoring device has not been shown because they may be any conventionalequipment, but the invention contemplates the combination of such slipsand packer with the firing "head so as .to permit the firing of the gunperforator, the sampling of the fluid, or the permanent location :of thetool in the well for flowing or pumping'purposes.

What is claimed is:

1. A'firingmechanism for gun perforators comprising -a body, a detonatorcap therein aIhammer to strike said cap, spring means to be cocked tosnap said hammer, means to retractsaidhamm'eragainst said springincluding arod movable axially to lift said hammer axially, and .meansmovable relative to said body upon rotation .of said body relativethereto to release saidrod.

'2. Airing mechanism for gun perlorators comprising a body, a detonatorcap therein, .ahammer to strike said cap, springmeans to be cooked tosnap said hammer, means toretraotsaid hamer against said springincluding a .nod movable axially to lift said hammer axially, and meansmovable relative to said body upon rotation of said body relativethereto, and additional means to release said hammer after apredetermined movement thereof.

3. A firing head for gun .perforators including a body, a cage slidablyconnected thereto, a .mandrelfixed to said body and extending throughsaid cage, a threaded connection between said cage and mandrelso thatrotation of the mandrel and body relative to the cage eifects slidingmovement of the cage, .and firing means to .be cocked and released bysuch movement.

'4. A firing head for gun perforators including a body, a cage slidablyconnected thereto, .a mandrel fixed to said body .and extendingthroughsaid cage, .a. threaded connection between said cage and mandrelso that rotation of the mandrel andbody relative to the cage effectssliding movement of the cage, and firing means to be cocked and releasedby such movement, and additional means on the cage to drag on the wellcasing to hold the cage against rotation.

5. A firing head for gun perforators including a body, a cage slidablyconnected thereto, a mandrel fixed to said body and extending throughsaid cage, a threaded connection between said cage and .mandrel so thatrotation of the mandrel and body relative to the cage .eifects slidingmovement of the cage, and firing means to be cooked and released by suchmovement, said threaded.

connection including a split spr'ingnut andratchet thread so as to allowreturn of said mandrel.

6. A firing head for gun perforators including a body, a cage slidablyconnected thereto, a man drel fixed to said body and extending throughsaid cage, a threaded connection between said cage and mandrel so thatrotation of the mandrel and body relative to the cage efiects slidingmove ment of the cage, and firing means to be cocked and released bysuch movement, said threaded connection including a split spring nut andratchet thread so as to allow return of said mandrel to set slips or apacker in the well.

7. A firing head for gun perforators including a body, a cage slidablyconnected thereto, a mandrel fixed to said body and extending throughsaid cage, a threaded connection between said cage and mandrel so thatrotation of the mandrel and body relative to the cage effects slidingmovement of the cage, and firing means to be cocked and released by suchmovement, said mandrel being hollow so as to permit a flow of fluidtherethrough which results from the perforation.

8. A firing head for gun perforators including a body, a cage slidablyconnected thereto, a mandrel fixed to said body and extending throughsaid cage, a threaded connection between said cage and mandrel so thatrotation of the mandrel and body relative to the cage efiects slidingmovement of the cage, and firing means to be cocked and released by suchmovement, said firing means including a pull rod, firing hammer to beretracted thereby and a spring to be compressed by the retractinghammer.

9. A firing head for gun perforators including a body, a cage slidablyconnected thereto, a mandrel fixed to said body and extending throughsaid cage, a threaded connection between said cage and mandrel sothatrotation of the mandrel and body relative to the cage effectssliding movement ofthe cage, and firing means to be cocked and releasedby such movement, said firing means including a pull rod, firing hammerto be retracted thereby and a spring to be compressed by the retractinghammer, and a tapered face on which said hammer slides so as to releasefor firing after a predetermined movement.

10. A combination firing and flowing head for wells comprising a body, acage, means to effect relative longitudinal movement of said head andcage to effect firing of a gun perforator, an operating mandrelconnected to said body and having a flow passage therethrough to'allowflowing of the well after firing of the head.

11. A combination firing and flowing head for wellscomprising a body, acage, means to effect relative longitudinal movement of said head andcage to efiect firing of a gun perforator, an operating mandrelconnected to said body and having a flow passage therethrough to allowflowing of the well after firing of the head, said cage being adaptedfor connection to slips and a packer to direct the flow through saidmandrel.

12. The combination firing and flowing tool for wells including anoperating pipe having a hollow mandrel thereon and a gun perforatorfiring head body having a passage therein and connected to the mandrel,a cage on the body movable to effect firing of the gun perforator sothat fluid may flow through said mandrel and 13. The combination firingand flowing tool for wells including an operating pipe having a hollowmandrel thereon and a gun perforator firing head body having a passagetherein and connected to the mandrel, a cage on the body movable toefiect firing of the gun perforator by rotation of the pipe and bodyrelative thereto so that fluid may flow through said mandrel and pipe.

14. The combination firing and flowing tool for wells including anoperating pipe having a hollow mandrel thereon and a gun perforatorfiring head body having a passage therein and connected to the mandrel,a cage on the body movable to effect firing of the gun perforator sothat fluid may flow through said mandrel and pipe, and means to anchorand seal said tool in the well bore by manipulation of said pipe andcage after firing.

JAMES G. SMYLIE.

